Hello,

We have seen a WARNING message while fuzzing with syzkaller.

Kernel 5.15.165 on an x86_64

------------[ cut here ]------------ WARNING: CPU: 1 PID: 1592 at mm/page_alloc.c:5398 __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5398 Modules linked in: CPU: 1 PID: 1592 Comm: syz-executor777 Not tainted 5.15.165-rc1-305-ge122be7431ef1-syzk #1 Hardware name: Red Hat KVM, BIOS 1.16.0-4.module+el8.9.0+90052+d3bf71d8 04/01/2014 RIP: 0010:__alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5398 Code: 00 48 89 44 24 58 e9 fa fc ff ff 48 89 f2 48 89 c7 44 89 c6 e8 77 32 f2 ff 49 89 c7 e9 72 fd ff ff 80 e7 20 0f 85 d8 fe ff ff <0f> 0b e9 d1 fe ff ff a9 00 00 08 00 75 48 89 da 80 e2 7f a9 00 00 RSP: 0018:ffff88801c18fb58 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000000400c0 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000017 RDI: 0000000000040dc0 RBP: 1ffff11003831f6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000017 R14: 0000000000000000 R15: 0000000000000000 FS: 00007ff8aaa97740(0000) GS:ffff888107080000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff8aa38a520 CR3: 0000000022534000 CR4: 00000000000006e0 Call Trace: <TASK> alloc_pages+0x21e/0x3d0 mm/mempolicy.c:2185 kmalloc_order+0x31/0xb0 mm/slab_common.c:966 kmalloc_order_trace+0x19/0xa0 mm/slab_common.c:982 kmalloc include/linux/slab.h:596 [inline] kzalloc include/linux/slab.h:721 [inline] input_mt_init_slots+0xf6/0x620 drivers/input/input-mt.c:49 uinput_create_device+0x1e6/0x6e0 drivers/input/misc/uinput.c:327 uinput_ioctl_handler.isra.0+0x46f/0x15e0 drivers/input/misc/uinput.c:870 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x199/0x220 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x6c/0xd6 RIP: 0033:0x7ff8aa38a53d Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc7eebe838 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff8aa38a53d RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003 RBP: 00000000004017a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 431bde82d7b634db R13: 00007ffc7eebe960 R14: 0000000000000000 R15: 0000000000000000 </TASK> ---[ end trace ced5c0b641032976 ]---

Fix commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

Can you please backport this commit to stable kernels on 5.15.y (and other stable kernels 6.1.y, 6.6.y)

commit: 99d3bf5f7377 ("Input: MT - limit max slots")

author Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2024-07-29 21:51:30 +0900 committer Linus Torvalds torvalds@linux-foundation.org 2024-07-29 10:44:48 -0700 commit 99d3bf5f7377d42f8be60a6b9cb60fb0be34dceb (patch) tree 78dd9dff2065f2eaf5a9e981f84d56eed2346d10 parent 3894840a7a11aa06cc3b0d5a2d1b5f6878127903 (diff) download linux-99d3bf5f7377d42f8be60a6b9cb60fb0be34dceb.tar.gz Input: MT - limit max slots syzbot is reporting too large allocation at input_mt_init_slots(), for num_slots is supplied from userspace using ioctl(UI_DEV_CREATE).

Since nobody knows possible max slots, this patch chose 1024.

Reported-by: syzbot syzbot+0122fa359a69694395d5@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0122fa359a69694395d5 Suggested-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Diffstat -rw-r--r-- drivers/input/input-mt.c 3 1 files changed, 3 insertions, 0 deletions diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c index 14b53dac1253bf..6b04a674f832a0 100644 --- a/drivers/input/input-mt.c +++ b/drivers/input/input-mt.c @@ -46,6 +46,9 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots, return 0; if (mt) return mt->num_slots != num_slots ? -EINVAL : 0; + /* Arbitrary limit for avoiding too large memory allocation. */ + if (num_slots > 1024) + return -EINVAL;

mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL); if (!mt)